Apparatus for extracting metals from their ores.



PATENTED APR. 2,1907.

' 0; R. ARNOLD. APPARATUS FOR BXTRAOTING METALS FROM THEIR ems.

APPLICATION FILED JUNE 4, 1904.

2 RM A A; MB A .m wm

WITNESSES:

A TTORIVEVS rm: unkms PETERS co, WASHINGTON, D. c.

UNITED STATES PATENT OFFICE.

CRAIG RITCHIE ARNOLD, OF PHILADELPHIA, PENNSYLVANIA.

APPARATUS FOR EXTRACTING METALS FROM THEIR ORES.

Specification of Letters Patent.

Patented April 2, 1907.

To all whom, it may concern:

Beit known that I, CRAIG RITCHIE ARNOLD, a citizen of the United Sates,and a resident of Philadelphia, in the county of Philadelphia and Stateof Pennsylvania, with post-office address as above, have inventedcertain new and useful Improvements in Apparatus for Extracting Metalsfrom Their Ores, of which the following is a specification.

My invention relates to apparatus employed in processes of recoveringmetals from ores, tailings, concentrates, slimes, or other metal-bearingsubstances by agitating a pulp consisting of the metal-bearing substanceand a suitable chemical solution in the presence of air employed as anoxidizing agent in the process.

The main object of the invention is to provide a simple and effectiveapparatus suitable for use in the cyanid process of recovering gold,silver, and other precious metals and which in addition to a thoroughand complete agitation of the pulp in the presence of the oxidizingmedium shall be entirely free from the objections attendant upon the useof the apparatus heretofore employed.

To this end the invention consists in the combination of apparatushereinafter described and then specified in the claims.

The accompanying drawings illustrate in side elevation and section anapparatus embodying my invention.

5 indicates the treating tank or vat, which may be of any desired formand is provided with a hopper through which the tank may be charged.

7 indicates the discharge-opening, through which the treated pulp isemptied into a settling-tank 15 or otherwise removed for recovery of thesolution and separation of the metallic constituents thereof.

The tank is preferably made of conical form at its bottom to assist inthe discharge of the pulp and, further, to facilitate the movement ofthe mass of pulp under the action of the stream of gas introduced intothe mass of the pulp at the lower end of the tank through pipe 25,having a suitable opening or openings within the tank or vat. Said pipeopens into the body of pulp at or near the center of the bottom of thetank, so as to be in proper position to agitate the pulp thoroughly bythe action of the stream of gas drawn through the pipe 25 by the vacuummaintained above the body of pulp.

26 is a suitable pipe opening into the gasspace at the top of the tankand through which the gas or gases therein are removed by suctionproduced by the action of a suitable pump, the function of which is tomaintain a partial vacuum in the tank 5.

The pipe 25 communicates with the atmosphere, so that by the operationof the vacuumpump connected to the pipe 26 a flow of gas will beproduced by suction through pipe 25 and up through the pulp in the tank5 to agitate the same. Interposed between pipe 25 and the atmosphere isa suitable generator 4 of a halogen or other reducing gas. Saidgenerator is here typified by an ordinary Woulfe bottle.

As a means for maintaining a partial vacuum in the treating tank andpipe 26 or other passages by which the excess or waste gases areconducted away I prefer to employ a vacuum-pump 9, which may be of thewellknown Sprengel type and preferably operated bywater conductedthereto under pressure by a pipe provided with a stop-cock 10, saidwater being delivered through pipe 11 into the pot or tank 12,containing water in which the outlet of the pipe 11 is submerged. Thehead of water and the volume of flow thereof will obviously determinethe degree of vacuum which can be maintained, and hence the rate of flowof air introduced into the body of pulp through the pipe 25, which rateof flow in order to satisfy the requirements of my invention must besufiicient to thoroughly agitate the body of pulp, and so bring all themetal-bearing constituents thereof into effective contact with theoxidizing medium, which in the case supposed is air.

By the use of a vacuum-pump of the water type having its outletsubmerged as described I secure the advantage that the waste or excessgases passing from pipe 26 to and through the pump will commingle withthe waste water and produce ,a harmless compound. Ordinarily, however, Iprefer to interpose between the pump and the tank one or more absorptionvats or tanks 8 of the ordinary type, in which the gas is caused to passthrough a solution of material suitable for chemically uniting with thegas or gases taken from the tank and so operating either to render thesame harmless or to recover the same in suitable form to permit therecovered elements to be again employed in the treating-tank. Thus, forinstance, in the cyanid process said absorption-tanks 8 might contain amaterial suitable for uniting IIO with the hydrocyanic-acid gasgenerated in thetreating-tank, in which case they would be preferablychargedwith some caustic solut1onsuch as a solution of caustic soda,caustic lime, caustic potash, or any other caustic alkali or alkalineearth adapted to unite with or absorb hydrocyanic acid-thus producing asimple cyanid adapted to act as a solvent for gold, silver, or othermetalbearing ore or pulp undergoing treatment in the tank or vat 5. Bythus combining absorption tanks or bottles and a hydraulic exhaust-pumpin the passage between the outlet of the tank and the atmosphere I amable to insure the complete absorption of any of the deleteriousproducts of the process being conducted in the tank 5 and at the sametime am enabled to thoroughly recover the valuable released gases orelements for use in connection with fresh bodies of ore or othermetal-bearing substances. This result is due to the fact that whenproper attention is paid to the character or strength of the absorbingsolution in the absorption vats or tanks 8 such solution will thoroughlyabsorb the hydrocyanic gas generated or released in the pulp-containingtank; but if any such gas should possibly pass the absorption tanks orvats it, together with any of the other deleterious gases which thesolution fails to take up, will commingle with the Waste water of thepump and be rendered harmless.

The generating material may be introduced into the bottle 4 through thefunnel 13. Said bottle is preferably of glass, so that the quantity ofsuch material can be observed. Preferably the air introduced into saidbottle throu h pipe 1 is carried through the heater-coil 2 in a heater3, and the pipe 1 may be provided with an inlet-funnel 14 for theintroduction of any oxidizing or reducing agent. It will be understood,also, that the contents of the bottle 4 may be such as to produce otheroxidizing or reducing agents besides bromin. Also, as will be obvious,when bromin is employed the absorption tanks 8 may be charged with asolution of alkali, which will combine with the bromin or other gas ofthe halogen group that may be passed through the pulp and escape by thepipe 26.

In the operation of the apparatus described the pulp in the tank 5 ismixed with a suflicient amount of solution to render it capable of beingagitated or stirred by the action of the gases drawn up through the samefrom the pipe 25 to the space with which the pipe 26 communicates, andin which space the partial vacuum is maintained, as already described.

It will be seen that in my process the agitating is produced not underpressure of gas, but under a partial vacuum in practically all the pipesor spaces in which the gas exists, and the escape of gas is thus avoidedeven though there should be a defect or opening through which leakagewould otherwise occur. This advantage applies obviously to the inlet aswell as to the exit pipe or space, wherein the excess or waste gasesresulting from the treatment exist. Moreover, it will be seen that thechemical actions in thetank take place under reduced pressure, whichcondition I find in practice adds very greatly to the rapidity of theoperation and is an important factor in the practical operation ofrecovering the metal from the ore.

I/Vhat I claim as my invention is 1. The combination substantially asdescribed in an apparatus for recovering gold and silver by the cyanidprocess, of a pulpcontaining vat or tank, an inlet at the bottom of thetank-opening in position to cause gas when introduced in'sufiicientquantity and under sufficient head to thoroughly agitate any pulpcontained therein, connections leading from the outside atmosphere tosaid inlet, a I/Voulfe bottle interposed in such connections and adaptedto supply the entering air with a gas of the halogen group, an outletfrom said pulp-containing tank connected to the upper part thereof, ahydraulic exhaustpump connected to said outlet and an absorption tank orvat interposed in the connection between the tank and the exhaustpumpsaid pump being adapted to produce by exhaustion a flow of air throughthe Woulfe bottle and into the tank in suflicient amount to thoroughlyagitate the pulp, as and for the purpose described.

2. In an apparatus for recovering gold and silver from ores, thecombination substantially as described, of a closed tank adapted to holda metal-bearing pulp and having an inlet at the bottom thereof, pipes orconnections leading from the outside atmosphere to said inlet, a VVoulfebottle and a heater interposed in said connections, an outlet from thetop of said tank and a hydraulic exhaustpump and an algWtank connectedto said outlet, the -sorption-tank being interposed between the outletand the pump, as and for the purpose described.

Signed at Philadelphia, in the county of Philadelphia and State ofPennsylvania, this 30th day of April, A. D. 1904:.

CRAIG RITCHIE ARNOLD.

Witnesses:

J. W. H. UNDERWOOD, M. G. GARLAND.

